Summary of web page and browser compatibility issues (draft1)

I. Javascript
1. The getyear method of the date object
The results returned by IE getyear () are the same as those returned by getfullyear (), but ecma262 explicitly specifies that getyear returns "year-1970 ". Some websites use getyear to return the Year, which leads to logical differences between standard browsers such as IE and ff.
Ii. Dom
1. event model
2.doc ument. elementfrompoint
This method of document is extended by IE. The Dom node of the element can be returned according to the client Region coordinates of the viewport. Safari also supports this method, but the coordinates represent the coordinates after the webpage content layout (the coordinates are the client zone coordinates of the browser window ). The difference between the two results in that if you want to obtain the element node through the pointer of the mouse, ie is the client region coordinate (clientx, clienty) of the client that can directly event the returned element, however, Safari uses scrollx and scrolly to return the result. In the sense of this interface, both are reasonable. The meaning of the coordinate is not clearly defined in msdn, but IE is easier to use from the interface, while safari needs to convert the coordinates.
Iii. CSS
Iv. Layout
V. Plug-ins and ActiveX
As we all know, ie is compatible with third parties Program ActiveX technology is used, while Firefox, Safari, chrome, and opera adopt the plug-in Technology of npapi. At the interface level, the plug-in interface layers are lower (both are C function pointers), and abstract interfaces and data types are used to encapsulate the interaction logic between browsers and third-party programs, however, browsers and plug-ins are tightly coupled. ActiveX shields process and thread models and is a loosely coupled interaction method. This is also why the valid ActiveX does not cause IE to crash in IE, but the plug-in with the same function may cause the browser to crash. The difference in this feature is also one of the major differences in browser compatibility.
Vi. Miscellaneous
1. it is not reasonable for the forum to set cookies based on the sub-version of the browser in the useragent, because the original cookie is effective as the browser version changes.